To Maximize Your EV's Range, Think of Eggs

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To Maximize Your EV's Range, Think of Eggs

The first time you drive an electric vehicle, you will do one of two things. It is inevitable. You will drive like old Aunt Edna, creeping along absolutely petrified of draining the battery. Or you will drive like Sebastian Vettel, hammering the go-pedal and relishing the torque of an electric motor.

That passed as we got a feel for how many miles we could squeeze from the 16 kilowatt-hour pack. The Japanese-spec i-MiEV we drove has a range of 60 to 70 miles. Not a lot, but plenty for Bay Area commuting. Once we figured this out, we'd often stomp on the accelerator because, frankly, it's fun. The i-MiEV is no Tesla Roadster Sport, but it is surprisingly snappy.

There is, of course, a happy medium between these two extremes. So we talked to a couple of people who've racked up a lot of miles in EVs to find out the best way to drive cars with cords.

First we called Paul Scott, a founder of the advocacy group Plug-In America. He's been driving his Toyota RAV4 EV since 2002 and has more than 87,000 miles on the odometer. In all that time he's never once run out of juice (the RAV4 EV has a range of about 100 miles). Still, even he went through a bit or range anxiety at first. Everyone does.

"It takes a little time and practice to understand how to drive (an EV) and how far you can go on each little tick of the gauge," he said. "You'll want to know how far down it can go and how far you can go before you get into trouble."

You can go really, really far down. Scott's rigged his RAV4 with a super-precise state of charge meter and has on occasion rolled into the driveway with less than one percent left. That's like having a few tablespoons of gas in your tank. He doesn't recommend making a habit of it, though, and tries to keep his battery at 25 percent or higher.

Scott says the key to maximizing range is thinking like a hypermiler. Make every bit of energy count. This is a good policy no matter what you drive, but it's doubly important in an EV because you can't pull into a service station and charge up. Whatever you do, don't stomp on it. Accelerate gradually away from traffic lights, stop signs and so forth. Yes, that old lady in the Cutlass will probably out accelerate you. Let her.

"I've found that the people who take off quickly usually don't gain anything on me," Scott said. "I usually catch them by the next light and all they've done is burned a lot more energy."

Accelerating slowly in an EV can be tricky because "everyone gets so addicted to that torque, to that 'whoosh' feeling," said David Patterson, a senior engineer at Mitsubishi Motors R&D. But you'll chew up a lot of power feeding that habit.

"If you drive with the proverbial egg under the throttle, you'll get the maximum range," Patterson said.

Eggs are a good analogy. Imagine they're everywhere. Use a light touch on the accelerator and the brake and mind your speed. The faster you go, the more energy you use. Stick to the speed limit and maintain a steady pace. Unnecessary fluctuations draw a lot more power. (Of course, these points are all true of fossil fuel-burning vehicles as well.) Another trick is maximize your regenerative braking, which sends some of the energy generated during braking back to the battery pack.

Regen will feel a bit odd at first, but it's a lot like engine braking in a conventional car. The amount of energy (which otherwise would be lost as heat) sent back to the pack varies with the car. In the i-MiEV, it's about one-third. Not a lot, but every little bit helps. You'll find yourself using the brakes less often because the car slows itself through regen.

On the other hand, some old-school EV drivers prefer to "freewheel," which is a lot like sticking your gasoline powered car in neutral and coasting, instead of using regen.

"On a flat road or slight downhill, you want to take advantage of the fact that an efficient EV doesn't slow as much as a gas car and therefore negates the need to speed back up," said Chelsea Sexton, a longtime EV advocate. "The most efficient braking is that which you never do."

The i-MiEV, for example, has drive, eco and braking modes. "Drive" feels a lot like a conventional car. "Eco" cuts motor output 20 percent and ramps up the regen to improve range. "Braking" provides full power and maximum regen for optimal range. The regenerative braking feels a lot like the engine braking experienced descending a steep hill.

We mixed and matched modes. We'd tool around in eco mode. When we needed more oomph – accelerating onto the highway, for example – we'd drop it into braking mode. Once we hit cruising speed, we'd go back to eco. Then we'd use braking mode to scrub off speed without hitting the brake pedal. It all became second nature within a day or two, and anyone who's driven a stick will have no trouble with it.

Judicious use of accessories like air conditioning also will boost your range. We quickly discovered the i-MiEV's defroster took a bite out of the battery. A/C takes a bigger bite. Managing your power consumption is important, which is why some cars, like the Nissan Leaf, provide a wealth of real-time information outlining just how much juice each system is sucking down. That's helpful because although accessories are a relatively small draw they add up.

Of course, all of these steps are necessary only if you suspect you're going to need every bit of range before you can charge up. If you've got the juice, or someplace to charge the car when you're not home, then let 'er rip.

"EVs tend to be really fun to drive, so I always encourage people to do exactly that when they're well within bounds of whatever range they have," said Sexton, who is known for her heavy right foot. "I don't advocate hypermiling all the time."

Neither do we. We used a mix of hypermiling tricks and conventional driving during the three weeks we had the i-MiEV. In all that time, we never used more than two-thirds of the energy in the pack and we only ever plugged in at home. So if range won't be an issue, there's no reason at all not to drive an EV just like you'd drive a conventional car.

We found 60 miles was plenty for our needs, even without finding someplace to charge up during the day. Obviously that won't work for everyone. Other cars with bigger batteries will provide greater range, but here too, your range may vary. That's one reason Nissan says drivers will "a range of ranges" with the Leaf, which has a claimed range of 100 miles.

But until we've got a broad public charging infrastructure in place – with lots of so-called Level 3 quick-chargers that can do the job in 20 or 30 minutes – and/or EVs with range well over 100 miles, it is best to approach driving an electric car much like you'd approach driving an airplane: Have a flight plan. Know how far you're going and whether you can plug in at the other end. It sounds like a radical change, and in some ways it is. But after spending three weeks with an electric car, we discovered it's not as big a hassle as you might think.

"It's more about thinking more than doing more," Sexton said, "but after a while it becomes very intuitive."